WASHINGTON (AP).- The United States Holocaust Memorial Museum says 30 million visitors have now come through its doors.

The museum said Wednesday that the milestone was passed this week. The museum has been open since April 1993. A museum spokesman says 1.75 million people visited last year.

Museum officials also note that 88 heads of state and more than 3,500 foreign officials from more than 130 different countries have toured the museum.

Washington's Smithsonian Institution museums counted 30 million visits combined in 2009. The most-visited museum was the natural history museum with 7.4 million visitors. Admission to both the Smithsonian museums and the Holocaust museum is free.